A decade ago, more than 3,300 criminal immigrants were sent to private prisons under two 10-year contracts the Federal Bureau of Prisons signed with CCA worth $760 million. Now, the agency is paying the private companies $5.1 billion to hold more than 23,000 criminal immigrants through 13 contracts of varying lengths.

CCA was on the verge of bankruptcy in 2000 due to lawsuits, management problems and dwindling contracts. Last year, the company reaped $162 million in net income. Federal contracts made up 43 percent of its total revenues, in part thanks to rising immigrant detention. GEO, which cites the immigration agency as its largest client, saw its net income jump from $16.9 million to $78.6 million since 2000.